GM to replace Pistons
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Teching In
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GM to replace Pistons I took my 02 Firebird into the shop last week to determin about the clicking noise. They claim the TSB regarding O-Ring has already been done on my car. I have a clicking lifter like noise until it reaches full operating temperature.
They told me it was Piston Slap and it doesn't harm the motor. But GM will replace my pistons with a new set of pistons if I would like that fix, however they will not replace the rings on the pistons they have to match the rings to the cylinder they come out of. They also told me that GM said to put the largest piston in the kit in Bank 1 and the Smallets in Bank2.
Has anyone else had their pistons replaced due to the piston slap with this fix that GM is offering.
They told me it was Piston Slap and it doesn't harm the motor. But GM will replace my pistons with a new set of pistons if I would like that fix, however they will not replace the rings on the pistons they have to match the rings to the cylinder they come out of. They also told me that GM said to put the largest piston in the kit in Bank 1 and the Smallets in Bank2.
Has anyone else had their pistons replaced due to the piston slap with this fix that GM is offering.
Piston slap is normal and I wouldn't worry about changing pistons unless you have a large oil consumption problem. If they did replace your pistons, the cylinders would need to be honed, the rings would need to be replaced, and of course most of this couldn't be done without removing the crank and rods, which would mean they would basically have to rebuild your short block.
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From: H-town
i am a tech at a GM dealer and i have done several of these piston replacements under warrenty myself. it is true that GM does not alow us to replace the rings since they put there own pattern in to the cylinder bore that they are in. if we did replace the rings, the motor will have to be honed but like i said, they will not alow this for cost reasons. the new pistons come with a better coated skirt desing to keep the noise down but being your car is a 02 it should already have this better piston in it. i am suprised that they did not tell you that it is normal. hear is a pic of both pistons together. the one on the left is the updated one and the one on the right is the older desing.
TECH Apprentice
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From: Nottingham, Notts, England, UK
Nice pic. So the updated piston seems to have some teflon added to the skirt. That ought to take up some slack as well as freeing up a few more horses. As for the rings, well you need to keep the old rings as they are already bedded in.
Replacing the pistons won't really help anything. Some slapping noise is inherant to this motor, but some engines are definitely louder than others. Some cylinders are bored slightly larger than they should be and need oversized pistons to completely fix the problem.
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From: H-town
Originally Posted by Haytoes
does this problem also occur in the 5.3L truck motor? Mine is awfuly loud on cold starts.
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My 02 ticks quite loudly on cold start, and keeps doing it until it warms up. Even on a warm start, it does it for about a minute. Strangly enough, if I rev it to 1,500 RPM and let it drop back to idle, the ticking will stop for ~ 20 seconds. Still, I'm not that concerned. She runs like a sewing machine (okay, as well as a TR6 eqipped sewing machine would) and doesn't burn a drop of oil.
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Teching In
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Thanks for all of your responses. My symptoms are exactly like Drake has.'
Mine has a ticking noise after temp reaches 100 to 180 deg if I rev it a bit it goes away then comes back in about 20 sec only does this until I hit full operating temperature. After that no Ticking. No oil consumption.
Now you all have me debating if I should have them tear into my engine and replace the pistons or not.
Also my car is Bone stock nothing done to it YET :-)
Mine has a ticking noise after temp reaches 100 to 180 deg if I rev it a bit it goes away then comes back in about 20 sec only does this until I hit full operating temperature. After that no Ticking. No oil consumption.
Now you all have me debating if I should have them tear into my engine and replace the pistons or not.
Also my car is Bone stock nothing done to it YET :-)
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From: H-town
to tell you the truth, once the pistons are replaced under warrenty there still will be some noise that you might not be happy with. like i had said, GM considers this normal. personally if i was in your shoes, i would not worry about the noise.
Originally Posted by terrygs31
Thanks for all of your responses. My symptoms are exactly like Drake has.'
Mine has a ticking noise after temp reaches 100 to 180 deg if I rev it a bit it goes away then comes back in about 20 sec only does this until I hit full operating temperature. After that no Ticking. No oil consumption.
Now you all have me debating if I should have them tear into my engine and replace the pistons or not.
Also my car is Bone stock nothing done to it YET :-)
Mine has a ticking noise after temp reaches 100 to 180 deg if I rev it a bit it goes away then comes back in about 20 sec only does this until I hit full operating temperature. After that no Ticking. No oil consumption.
Now you all have me debating if I should have them tear into my engine and replace the pistons or not.
Also my car is Bone stock nothing done to it YET :-)
Last edited by taqwache; Sep 25, 2004 at 12:30 PM.
Originally Posted by taqwache
... personally if i was in your shoes, i would not worry about the noise.
Personally, I don't even like the way they handle my car, even for minor work. It seems like every time I've taken it back, she's wound up with scratches on the interior that weren't there before. (Mind you, I'm ultra picky about that). I also found a straw wrapper under the seat once after leaving the car overnight... wasn't too happy about that.
Honestly, the thoughts of letting a GM garage touch my engine even for something semi-major makes me feel sick. I certainly wouldn't let them "fix" something that doesn't seem to be a problem for thousands of other LS1 owners.
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From: H-town
Originally Posted by Drake
Personally, I don't even like the way they handle my car, even for minor work. It seems like every time I've taken it back, she's wound up with scratches on the interior that weren't there before. (Mind you, I'm ultra picky about that). I also found a straw wrapper under the seat once after leaving the car overnight... wasn't too happy about that.
Honestly, the thoughts of letting a GM garage touch my engine even for something semi-major makes me feel sick. I certainly wouldn't let them "fix" something that doesn't seem to be a problem for thousands of other LS1 owners.
Last edited by taqwache; Sep 25, 2004 at 12:36 PM.
Piston slap is due to excess piston/cylinder wall clearance. New rings won't help that. It's good to see some GM Techs being so forthright about the procedures at the GM dealerships. It just seems chickenshit to me to put the same rings back in after doing all the work required to get the pistons out. Taking them out the top or bottom is a lot of work either way and to skimp on honing and a new set of rings at that point is taking nickle and diming to a level I've not heard of when it comes to a motor tear down. You have to take the old rings off of the pistons your replacing anyway so why not just slap on a NEW set of rings at that point and spend a few minutes more honing the cylinder walls before you put the pistons back in? That's assuming the motor is low milage enough and a ridge has not built up at the top of the cylinder bores. I hope GM doesn't require their techs to reuse oil and gaskets too after a rebuild!
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From: H-town
Originally Posted by terrygs31
taqwache,
Have you ever seen damage done to the engine from minor piston slap if there wasn't any oil consumption ?
Have you ever seen damage done to the engine from minor piston slap if there wasn't any oil consumption ?
. but as of now that is all over with. GM has not had a problem in quite a while. the last time a Gen3 was replaced at my dealer was a while ago and it was because of spun bearings. these motors are pretty bullit proof now. 
TECH Enthusiast
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From: Warner Robins, GA
I've had an AVM tell me to take the extended warranty when I complained about piston slap. His reasoning, and I'll quote. "GM will replace your 02 LS6 with another 02 LS6. Chances are very good that you'll have the same problem not to mention that the mechanics don't have the time required to do a proper job. Do you really want them touching your car? Now, I can offer you...."
Our cars are appliances and if they're defective, oh well, too bad, so sad. My suggestion for you guys with slappers is to take it to a mechanic who knows what they're doing and have them take the engine out and have it bored for oversized pistons. While they're at it, might as well throw a forged bottom end in it as well.
I'm thinking of a 427 for my vette and looking around for a good shop to do the work!
Our cars are appliances and if they're defective, oh well, too bad, so sad. My suggestion for you guys with slappers is to take it to a mechanic who knows what they're doing and have them take the engine out and have it bored for oversized pistons. While they're at it, might as well throw a forged bottom end in it as well.
I'm thinking of a 427 for my vette and looking around for a good shop to do the work!
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From: Grand Rapids, Michigan
I've seen on various fourms that some people that had the pistons replaced noticed the slap come back after a 1000mi or so, kinda like when they were new. When I bought my car I went with a very keen ear for PS and was very happy that when I fired her up cold in the dealers lot it was very quiet with no sign of PS, so I made the purchase.....well at 800mi it started to tick and now with 15,000mi on the clock it is very loud and lasts for about 10min and will still do it after I re-start it with a warm motor....needless to say i'm not happy.
Originally Posted by AK's WS6
... I fired her up cold in the dealers lot it was very quiet with no sign of PS, so I made the purchase.....well at 800mi it started to tick and now with 15,000mi on the clock it is very loud and lasts for about 10min and will still do it after I re-start it with a warm motor....needless to say i'm not happy.
Assuming it's an undersized piston/oversized cylinder problem, I guess the piston could be expanding enough once it's warmed up to kill the ticking.
Originally Posted by Drake
I also found a straw wrapper under the seat once after leaving the car overnight... wasn't too happy about that.
